function doUnsecure(secureValue, Password, Signature, newLines) 
{
	var sc = new SecureContext(secureValue, Signature, newLines);
	
	if (!sc.unsecure(Password)) 
	alert('Invalid password used.');
	
	return sc.strText;
}

function password(strpasswd) 
{
	this.strpasswd = strpasswd;
	this.getHashValue   = password_getHashValue;
	this.getpermutation = password_getpermutation;
}

function password_getHashValue() 
{
	var m = 907633409;
	var a = 65599;
	var h = 0;

	for (var i = 0; i < this.strpasswd.length; i++) 
	h = (h % m) * a + this.strpasswd.charCodeAt(i);

	return h;
}

function password_getpermutation() 
{
	var nNUMELEMENTS = 13;
	var nCYCLELENGTH = 21;

	pg = new permutationGenerator(nNUMELEMENTS);
	
	var anCycle = new Array(nCYCLELENGTH);
	var npred   = this.getHashValue();

	for (var i = 0; i < nCYCLELENGTH; i++) 
	{
		npred = 314159269 * npred + 907633409;
		anCycle[i] = npred % pg.nNumtranspositions;
	}
	return pg.fromCycle(anCycle);
}

function permutationGenerator(nNumElements) 
{
	this.nNumElements = nNumElements;
	this.antranspositions = new Array;
	var k = 0;
	
	for (i = 0; i < nNumElements - 1; i++)
		for (j = i + 1; j < nNumElements; j++)
		this.antranspositions[ k++ ] = ( i << 8 ) | j;

		// keep two positions as lo and hi byte!
		this.nNumtranspositions = k;
		this.fromCycle = permutationGenerator_fromCycle;
}

function permutationGenerator_fromCycle(anCycle) 
{
	var anpermutation = new Array(this.nNumElements);

	for (var i = 0; i < this.nNumElements; i++) 
	anpermutation[i] = i;

	for (var i = 0; i < anCycle.length; i++) 
	{
		var nT = this.antranspositions[anCycle[i]];
		var n1 = nT & 255;
		var n2 = (nT >> 8) & 255;

		nT = anpermutation[n1];
		anpermutation[n1] = anpermutation[n2];
		anpermutation[n2] = nT;
	}
	return anpermutation;
}

function SecureContext(strText, strSignature, bEscape) 
{
	this.strSIGNATURE = strSignature || '';
	this.bESCApE = bEscape || false;
	this.strText = strText;
	this.escape = SecureContext_escape;
	this.unescape = SecureContext_unescape;
	this.transliterate = SecureContext_transliterate;
	this.encypher = SecureContext_encypher;
	this.decypher = SecureContext_decypher;
	this.sign = SecureContext_sign;
	this.unsign = SecureContext_unsign;
	this.secure = SecureContext_secure;
	this.unsecure = SecureContext_unsecure;
}

function SecureContext_decypher(anperm) 
{
	var nRows = anperm.length;
	var nCols = this.strText.length / nRows;
	var anRowOfs = new Array;

	for (var i = 0 ; i < nRows; i++) 
	anRowOfs[ anperm[ i ] ] = i * nCols;

	var strplain = '';

	for (var i = 0; i < nCols; i++) 
	{
		for (var j = 0; j < nRows; j++)
		strplain += this.strText.charAt(anRowOfs[ j ] + i);
	}

	this.strText = strplain;
}

function SecureContext_encypher(anperm) 
{
	var strEncyph = '';
	var nCols = anperm.length;
	var nRows = this.strText.length / nCols;

	for (var i = 0; i < nCols; i++) 
	{
		var k = anperm[ i ];

		for (var j = 0; j < nRows; j++) 
		{
			strEncyph += this.strText.charAt(k);
			k += nCols;
   		}
	}
	this.strText = strEncyph;
}

function SecureContext_escape(strToEscape)
{
	var strEscaped = '';

	for (var i = 0; i < strToEscape.length; i++) 
	{
		var chT = strToEscape.charAt( i );

		switch(chT) 
		{
			case '\r': 
			strEscaped += '\\r'; 
			break;
			
			case '\n': 
			strEscaped += '\\n'; 
			break;
			
			case '\\': 
			strEscaped += '\\\\'; 
			break;
			
			default: strEscaped += chT;
   		}
	}
	return strEscaped;
}

function SecureContext_unescape(strToUnescape) 
{
		var strUnescaped = '';
		var i = 0;

		while (i < strToUnescape.length) 
		{
			var chT = strToUnescape.charAt(i++);
			
			if ('\\' == chT) 
			{
				chT = strToUnescape.charAt( i++ );

				switch(chT) 
				{

					case 'r': 
					strUnescaped += '\r';
					break;

					case 'n': 
					strUnescaped += '\n';
					break;
					
					case '\\': 
					strUnescaped += '\\'; 
					break;

					default: // not possible
   				}
			}
			else strUnescaped += chT;
		}
	return strUnescaped;
}

function SecureContext_secure(strpasswd) 
{
	var passwd = new password(strpasswd);
	var anperm = passwd.getpermutation();

	this.sign(anperm.length);
	this.transliterate(true);
	this.encypher(anperm);
}

function SecureContext_sign(nCols) 
{
	if (this.bESCApE) 
	{
		this.strText = this.escape(this.strText);
		this.strSIGNATURE = this.escape(this.strSIGNATURE);
	}

	var nTextLen = this.strText.length + this.strSIGNATURE.length;
	var nMissingCols = nCols - (nTextLen % nCols);
	var strpadding = '';  

	if (nMissingCols < nCols)
	for (var i = 0; i < nMissingCols; i++) 
	strpadding += ' ';

	var x = this.strText.length;
	this.strText +=  strpadding + this.strSIGNATURE;
}

function SecureContext_transliterate(btransliterate) 
{
	var strDest = '';
	var nTextIter = 0;
	var nTexttrail = 0;

	while (nTextIter < this.strText.length) 
	{
		var strRun = '';
		var cSkipped   = 0;

		while (cSkipped < 7 && nTextIter < this.strText.length) 
		{
			var chT = this.strText.charAt(nTextIter++);
			
			if (-1 == strRun.indexOf(chT)) 
			{
				strRun += chT;
				cSkipped = 0;
			}
			else cSkipped++;
		}

		while (nTexttrail < nTextIter) 
		{
			var nRunIdx = strRun.indexOf(this.strText.charAt(nTexttrail++));

			if (btransliterate) 
			{
				nRunIdx++;

				if (nRunIdx == strRun.length)
				nRunIdx = 0;
			}
			else 
			{
				nRunIdx--;
			
				if (nRunIdx == -1) 
				nRunIdx += strRun.length;
			}
			strDest += strRun.charAt(nRunIdx);
   		}
	}
	this.strText = strDest;
}

function SecureContext_unsecure(strpasswd) 
{
	var passwd = new password(strpasswd);
	var anperm = passwd.getpermutation()

	this.decypher(anperm);
	this.transliterate(false);
	return this.unsign(anperm.length);
}

function SecureContext_unsign(nCols) 
{
	if (this.bESCApE) 
	{
		this.strText = this.unescape(this.strText);
		this.strSIGNATURE = this.unescape(this.strSIGNATURE);
	}

	if ('' == this.strSIGNATURE) 
	return true;

	var nTextLen = this.strText.lastIndexOf(this.strSIGNATURE);
	
	if (-1 == nTextLen)
	return false;

	this.strText = this.strText.substr(0, nTextLen);
	return true;
}